Commit message: block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern

Add __GFP_ZERO flag for alloc_page in function bio_copy_kern to initialize
the buffer of a bio.

Signed-off-by: Haimin Zhang <tcs.kernel@gmail.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220216084038.15635-1-tcs.kernel@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
CVE: None
CWE: CWE-200
Vulnerability description: None

Project: linux
File: blk-map.c

static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
					       gfp_t gfp_mask)
{
	struct bio_map_data *bmd;

	if (data->nr_segs > UIO_MAXIOV)
		return NULL;

	bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
	if (!bmd)
		return NULL;
	memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
	bmd->iter = *data;
	bmd->iter.iov = bmd->iov;
	return bmd;
}

Project: linux
File: blk-map.c

int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
			struct rq_map_data *map_data,
			const struct iov_iter *iter, gfp_t gfp_mask)
{
	bool copy = false;
	unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
	struct bio *bio = NULL;
	struct iov_iter i;
	int ret = -EINVAL;

	if (!iter_is_iovec(iter))
		goto fail;

	if (map_data)
		copy = true;
	else if (blk_queue_may_bounce(q))
		copy = true;
	else if (iov_iter_alignment(iter) & align)
		copy = true;
	else if (queue_virt_boundary(q))
		copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);

	i = *iter;
	do {
		if (copy)
			ret = bio_copy_user_iov(rq, map_data, &i, gfp_mask);
		else
			ret = bio_map_user_iov(rq, &i, gfp_mask);
		if (ret)
			goto unmap_rq;
		if (!bio)
			bio = rq->bio;
	} while (iov_iter_count(&i));

	return 0;

unmap_rq:
	blk_rq_unmap_user(bio);
fail:
	rq->bio = NULL;
	return ret;
}

Project: linux
File: blk-map.c

static struct bio *bio_copy_kern(struct request_queue *q, void *data,
		unsigned int len, gfp_t gfp_mask, int reading)
{
	unsigned long kaddr = (unsigned long)data;
	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
	unsigned long start = kaddr >> PAGE_SHIFT;
	struct bio *bio;
	void *p = data;
	int nr_pages = 0;

	/*
	 * Overflow, abort
	 */
	if (end < start)
		return ERR_PTR(-EINVAL);

	nr_pages = end - start;
	bio = bio_kmalloc(gfp_mask, nr_pages);
	if (!bio)
		return ERR_PTR(-ENOMEM);

	while (len) {
		struct page *page;
		unsigned int bytes = PAGE_SIZE;

		if (bytes > len)
			bytes = len;

		page = alloc_page(GFP_NOIO | __GFP_ZERO | gfp_mask);
		if (!page)
			goto cleanup;

		if (!reading)
			memcpy(page_address(page), p, bytes);

		if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
			break;

		len -= bytes;
		p += bytes;
	}

	if (reading) {
		bio->bi_end_io = bio_copy_kern_endio_read;
		bio->bi_private = data;
	} else {
		bio->bi_end_io = bio_copy_kern_endio;
	}

	return bio;

cleanup:
	bio_free_pages(bio);
	bio_put(bio);
	return ERR_PTR(-ENOMEM);
}

Project: linux
File: blk-map.c

static void bio_copy_kern_endio_read(struct bio *bio)
{
	char *p = bio->bi_private;
	struct bio_vec *bvec;
	struct bvec_iter_all iter_all;

	bio_for_each_segment_all(bvec, bio, iter_all) {
		memcpy_from_bvec(p, bvec);
		p += bvec->bv_len;
	}

	bio_copy_kern_endio(bio);
}

Project: linux
File: blk-map.c

static int bio_uncopy_user(struct bio *bio)
{
	struct bio_map_data *bmd = bio->bi_private;
	int ret = 0;

	if (!bmd->is_null_mapped) {
		/*
		 * if we're in a workqueue, the request is orphaned, so
		 * don't copy into a random user address space, just free
		 * and return -EINTR so user space doesn't expect any data.
		 */
		if (!current->mm)
			ret = -EINTR;
		else if (bio_data_dir(bio) == READ)
			ret = bio_copy_to_iter(bio, bmd->iter);
		if (bmd->is_our_pages)
			bio_free_pages(bio);
	}
	kfree(bmd);
	return ret;
}

Project: linux
File: blk-map.c

static void bio_map_kern_endio(struct bio *bio)
{
	bio_invalidate_vmalloc_pages(bio);
	bio_put(bio);
}

Project: linux
File: blk-map.c

static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
{
	struct bio_vec *bvec;
	struct bvec_iter_all iter_all;

	bio_for_each_segment_all(bvec, bio, iter_all) {
		ssize_t ret;

		ret = copy_page_to_iter(bvec->bv_page,
					bvec->bv_offset,
					bvec->bv_len,
					&iter);

		if (!iov_iter_count(&iter))
			break;

		if (ret < bvec->bv_len)
			return -EFAULT;
	}

	return 0;
}

Project: linux
File: blk-map.c

static void bio_invalidate_vmalloc_pages(struct bio *bio)
{
#ifdef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
	if (bio->bi_private && !op_is_write(bio_op(bio))) {
		unsigned long i, len = 0;

		for (i = 0; i < bio->bi_vcnt; i++)
			len += bio->bi_io_vec[i].bv_len;
		invalidate_kernel_vmap_range(bio->bi_private, len);
	}
#endif
}

Project: linux
File: blk-map.c

int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
		    unsigned int len, gfp_t gfp_mask)
{
	int reading = rq_data_dir(rq) == READ;
	unsigned long addr = (unsigned long) kbuf;
	struct bio *bio;
	int ret;

	if (len > (queue_max_hw_sectors(q) << 9))
		return -EINVAL;
	if (!len || !kbuf)
		return -EINVAL;

	if (!blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf) ||
	    blk_queue_may_bounce(q))
		bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
	else
		bio = bio_map_kern(q, kbuf, len, gfp_mask);

	if (IS_ERR(bio))
		return PTR_ERR(bio);

	bio->bi_opf &= ~REQ_OP_MASK;
	bio->bi_opf |= req_op(rq);

	ret = blk_rq_append_bio(rq, bio);
	if (unlikely(ret))
		bio_put(bio);
	return ret;
}

Project: linux
File: blk-map.c

int blk_rq_append_bio(struct request *rq, struct bio *bio)
{
	struct bvec_iter iter;
	struct bio_vec bv;
	unsigned int nr_segs = 0;

	bio_for_each_bvec(bv, bio, iter)
		nr_segs++;

	if (!rq->bio) {
		blk_rq_bio_prep(rq, bio, nr_segs);
	} else {
		if (!ll_back_merge_fn(rq, bio, nr_segs))
			return -EINVAL;
		rq->biotail->bi_next = bio;
		rq->biotail = bio;
		rq->__data_len += (bio)->bi_iter.bi_size;
		bio_crypt_free_ctx(bio);
	}

	return 0;
}

Project: linux
File: blk-map.c

static struct bio *bio_map_kern(struct request_queue *q, void *data,
		unsigned int len, gfp_t gfp_mask)
{
	unsigned long kaddr = (unsigned long)data;
	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
	unsigned long start = kaddr >> PAGE_SHIFT;
	const int nr_pages = end - start;
	bool is_vmalloc = is_vmalloc_addr(data);
	struct page *page;
	int offset, i;
	struct bio *bio;

	bio = bio_kmalloc(gfp_mask, nr_pages);
	if (!bio)
		return ERR_PTR(-ENOMEM);

	if (is_vmalloc) {
		flush_kernel_vmap_range(data, len);
		bio->bi_private = data;
	}

	offset = offset_in_page(kaddr);
	for (i = 0; i < nr_pages; i++) {
		unsigned int bytes = PAGE_SIZE - offset;

		if (len <= 0)
			break;

		if (bytes > len)
			bytes = len;

		if (!is_vmalloc)
			page = virt_to_page(data);
		else
			page = vmalloc_to_page(data);
		if (bio_add_pc_page(q, bio, page, bytes,
				    offset) < bytes) {
			/* we don't support partial mappings */
			bio_put(bio);
			return ERR_PTR(-EINVAL);
		}

		data += bytes;
		len -= bytes;
		offset = 0;
	}

	bio->bi_end_io = bio_map_kern_endio;
	return bio;
}

Project: linux
File: blk-map.c

static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
{
	struct bio_vec *bvec;
	struct bvec_iter_all iter_all;

	bio_for_each_segment_all(bvec, bio, iter_all) {
		ssize_t ret;

		ret = copy_page_from_iter(bvec->bv_page,
					  bvec->bv_offset,
					  bvec->bv_len,
					  iter);

		if (!iov_iter_count(iter))
			break;

		if (ret < bvec->bv_len)
			return -EFAULT;
	}

	return 0;
}

Project: linux
File: blk-map.c

static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
		gfp_t gfp_mask)
{
	unsigned int max_sectors = queue_max_hw_sectors(rq->q);
	struct bio *bio;
	int ret;
	int j;

	if (!iov_iter_count(iter))
		return -EINVAL;

	bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_VECS));
	if (!bio)
		return -ENOMEM;
	bio->bi_opf |= req_op(rq);

	while (iov_iter_count(iter)) {
		struct page **pages;
		ssize_t bytes;
		size_t offs, added = 0;
		int npages;

		bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
		if (unlikely(bytes <= 0)) {
			ret = bytes ? bytes : -EFAULT;
			goto out_unmap;
		}

		npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);

		if (unlikely(offs & queue_dma_alignment(rq->q))) {
			ret = -EINVAL;
			j = 0;
		} else {
			for (j = 0; j < npages; j++) {
				struct page *page = pages[j];
				unsigned int n = PAGE_SIZE - offs;
				bool same_page = false;

				if (n > bytes)
					n = bytes;

				if (!bio_add_hw_page(rq->q, bio, page, n, offs,
						     max_sectors, &same_page)) {
					if (same_page)
						put_page(page);
					break;
				}

				added += n;
				bytes -= n;
				offs = 0;
			}
			iov_iter_advance(iter, added);
		}
		/*
		 * release the pages we didn't map into the bio, if any
		 */
		while (j < npages)
			put_page(pages[j++]);
		kvfree(pages);
		/* couldn't stuff something into bio? */
		if (bytes)
			break;
	}

	ret = blk_rq_append_bio(rq, bio);
	if (ret)
		goto out_unmap;
	return 0;

 out_unmap:
	bio_release_pages(bio, false);
	bio_put(bio);
	return ret;
}

Project: linux
File: blk-map.c

int blk_rq_unmap_user(struct bio *bio)
{
	struct bio *next_bio;
	int ret = 0, ret2;

	while (bio) {
		if (bio->bi_private) {
			ret2 = bio_uncopy_user(bio);
			if (ret2 && !ret)
				ret = ret2;
		} else {
			bio_release_pages(bio, bio_data_dir(bio) == READ);
		}

		next_bio = bio;
		bio = bio->bi_next;
		bio_put(next_bio);
	}

	return ret;
}

Project: linux
File: blk-map.c

static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
		struct iov_iter *iter, gfp_t gfp_mask)
{
	struct bio_map_data *bmd;
	struct page *page;
	struct bio *bio;
	int i = 0, ret;
	int nr_pages;
	unsigned int len = iter->count;
	unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;

	bmd = bio_alloc_map_data(iter, gfp_mask);
	if (!bmd)
		return -ENOMEM;

	/*
	 * We need to do a deep copy of the iov_iter including the iovecs.
	 * The caller provided iov might point to an on-stack or otherwise
	 * shortlived one.
	 */
	bmd->is_our_pages = !map_data;
	bmd->is_null_mapped = (map_data && map_data->null_mapped);

	nr_pages = bio_max_segs(DIV_ROUND_UP(offset + len, PAGE_SIZE));

	ret = -ENOMEM;
	bio = bio_kmalloc(gfp_mask, nr_pages);
	if (!bio)
		goto out_bmd;
	bio->bi_opf |= req_op(rq);

	if (map_data) {
		nr_pages = 1 << map_data->page_order;
		i = map_data->offset / PAGE_SIZE;
	}
	while (len) {
		unsigned int bytes = PAGE_SIZE;

		bytes -= offset;

		if (bytes > len)
			bytes = len;

		if (map_data) {
			if (i == map_data->nr_entries * nr_pages) {
				ret = -ENOMEM;
				goto cleanup;
			}

			page = map_data->pages[i / nr_pages];
			page += (i % nr_pages);

			i++;
		} else {
			page = alloc_page(GFP_NOIO | gfp_mask);
			if (!page) {
				ret = -ENOMEM;
				goto cleanup;
			}
		}

		if (bio_add_pc_page(rq->q, bio, page, bytes, offset) < bytes) {
			if (!map_data)
				__free_page(page);
			break;
		}

		len -= bytes;
		offset = 0;
	}

	if (map_data)
		map_data->offset += bio->bi_iter.bi_size;

	/*
	 * success
	 */
	if ((iov_iter_rw(iter) == WRITE &&
	     (!map_data || !map_data->null_mapped)) ||
	    (map_data && map_data->from_user)) {
		ret = bio_copy_from_iter(bio, iter);
		if (ret)
			goto cleanup;
	} else {
		if (bmd->is_our_pages)
			zero_fill_bio(bio);
		iov_iter_advance(iter, bio->bi_iter.bi_size);
	}

	bio->bi_private = bmd;

	ret = blk_rq_append_bio(rq, bio);
	if (ret)
		goto cleanup;
	return 0;
cleanup:
	if (!map_data)
		bio_free_pages(bio);
	bio_put(bio);
out_bmd:
	kfree(bmd);
	return ret;
}